pilot light clicks on(i can see it has lit) then i wait for the main burner to come on but it doesnt always come on.i have to switch the boiler on and off several times b4 it lights up properly and heats the water.not sure if its my imagination but it seems to work when i run the heat water for a while to let some of the hot water out of the tank?...would love sum help....many thanks adam

adam from essex, January 2010

If you have a fan that starts up before the boiler ignites , then there is also an AIR PRESSURE switch.

The problem may be due to a partially blocked plastic pipe between the switch & fan.

It goes via an inline metal restrictor ( inside the plastic tube) that can block up.

Remove the tube and suck/blow so that you can hear the Air Pressure Switch clicking...then replace the tube.

A very common Netaheat fault....on the boilers with the fan + pressure switch !

Beware scrapping the boiler as most parts are still available (Ebay etc) so don`t jump to any expensive conclusions.
(and don`t believe what the CH engineers or Gas Board tell you. These old boilers are built to last..

Reg, January 2010

could be controll box the offtern play up like this

erj, January 2010

sounds like the solenoid on the gas valve may be sticking.

Ian, January 2010

I am an unqualified muppet with respect to boilers - my Potterton Profile behaved this way and gradually got worse - the cause was a weak pilot flame failing to create enough heat for the next stage of operation.

My gas engineer cleaned out the pilot injector with a strand of thin wire (not recommended) and it was all fine - he dropped by a few days later and delivered a new injector (£35) but I have not needed it.

I hope your fault is as simple and cheap as the one I had.

Good luck...

Peccavi, January 2010